Not applicable.
Not applicable.
This invention relates to a composition and method for inflating and sealing inflatable objects. More particularly, the invention relates to a tire sealing and inflating composition and methods of using the composition.
Portable tire sealing and inflating devices have been used in emergency by a motorist to inflate and temporarily seal a pneumatic tire with a puncture wound when a service station or other repair facilities is not available to the motorist. The use of such devices, typically for an automobile, allows the motorist to drive the vehicle to a convenient location where the punctured or flat tire can be inspected and repaired. The availability of such devices obviates the need for the motorist to remove the flat tire from an automobile and replace it with a spare tire in order to reach a service station to repair the damaged tire. More importantly, such portable devices are extremely desirable if the motorist is stranded in a dangerous situation or if the motorist either does not have a spare tire or is physically unable to replace the flat tire with a spare tire.
Generally, a portable tire sealing and inflating device includes a conventional aerosol can containing a particular sealant composition which is introduced to the cavity of a flat tire through a valve stem. Typically, a length of flexible tubing connects a valve on the can with a threaded nozzle and connector on the remote end for attachment to and activation of the valve stem. Alternatively, the can is supplied with a pedestal valve for activation and dispensing of the contents without flexible tubing. A propellant within the can forces the sealant composition through the opened valve and into the tire. In this way, the tire is inflated and sealed.
At present time, most available portable tire sealing and inflating devices are based on aerosol, which is formed by a sealant composition and a propellant. Various hydrocarbons and chlorofluorocarbons have been used as propellants. However, hydrocarbon propellants are flammable, and the chlorofluorocarbon (CFC) propellants have been found to have a detrimental effect on the earth""s ozone layer and use thereof has been severely limited.
As a result, there has been a continuing effort to develop suitable CFC substitutes. However, several problems should be resolved when replacing chlorofluorocarbon or hydrocarbon propellants/inflators used in existing tire sealant and inflator compositions with a nonflammable, non-ozone depleting propellant/inflator. These problems are due to the differences between the vapor pressures of existing propellant/inflators and suitable CFC substitutes, relatively poor solvent properties of CFC substitutes, relatively high diffusion rates of CFC substitutes, and difficulties in obtaining consistent discharge rates throughout the life of tire sealer and inflator products when using a CFC substitute.
Additional consideration is the safety issue. Tire sealant/inflator cans are frequently stored in the trunks of vehicles, or worse, are exposed to direct sunlight. Therefore, internal pressure and can strength are very important safety parameters, which must be considered in producing a tire sealant/inflator composition. The higher the vapor pressure of a propellant, the higher the chance a container may burst in hot weather. Needless to say, it is important that any non-flammable, non-ozone depleting propellant/inflator used in a tire sealer and inflator composition be capable of storage in canisters which can be safely transported. The U.S. Department of Transportation (xe2x80x9cDOTxe2x80x9d) has issued regulations regarding the minimum performance characteristics of containers which can be used in interstate transportation. For example, for an aerosol can of the 2Q type, the vapor pressure inside the can must not exceed 180 psig at 130xc2x0 F. As such, any tire sealer and inflator products must comply with this requirement if a 2Q aerosol can is used.
1,1,1,2,-tetrafluoroethane, commonly known as HFC 134a, was developed as a replacement for chlorofluorocarbons. It is non-flammable, non-corrosive, and non-toxic. More importantly, it has an ozone depletion potential of zero. Consequently, there has been some interest in replacing CFC propellants by HFC 134a. However, attempts to substitute HFC 134a for conventional CFC propellants/inflators have not been met without difficulties. This is because HFC 134a has a vapor pressure of about 200 psig at 130xc2x0 F., which is too high to meet the DOT requirements for use in aerosol cans. Moreover, HFC 134a is not miscible with aqueous solvents, and therefore, tire sealant/inflator compositions made by replacement of existing hydrocarbon or CFC propellants with HFC 134a would require vigorous and frequent agitation before and during use to prevent disproportionate dispensing of the sealant.
For the foregoing reasons, there exists a need for a safe tire sealer and inflating composition and products made therefrom. Preferably, the tire sealing and inflating composition should be non-flammable, non-toxic, and environmentally-friendly.
The above need is met by embodiments of the invention in one or more of the following aspects. In one aspect, the invention relates to a tire sealer and inflating composition. The composition includes: (a) a sealant capable of sealing an opening in an inflatable object; (b) a non-flammable propellant having an ozone depletion potential of zero or substantially close to zero; and (3) one or more aromatic hydrocarbons capable of lowering the vapor pressure of the non-flammable propellant. Preferably, the composition has a vapor pressure less than about 180 psig at 130xc2x0 F. In some embodiments, the propellant is 1,1,1,2-tetrafluoroethane.
In another aspect, the invention relates to a method of sealing a puncture wound in an inflatable object. The method includes: (a) storing a tire sealer and inflating composition in a can having a vapor pressure less than about 180 psig at 130xc2x0 F., and (b) delivering the tire sealer and inflating composition to an inflatable object having a puncture wound. The tire sealer and inflating composition includes: (a) a sealant capable of sealing an opening in an inflatable object; (b) a non-flammable propellant having an ozone depletion potential of zero or substantially close to zero; and (c) one or more aromatic hydrocarbons capable of lowering the vapor pressure of the non-flammable propellant.
In still another aspect, the invention relates to a method of making a tire sealer and inflating composition. The method includes: (a) obtaining a sealant capable of sealing an opening in an inflatable object; (b) obtaining a non-flammable propellant having an ozone depletion potential of zero or substantially close to zero; and (c) mixing one or more aromatic hydrocarbons capable of lowering the vapor pressure of the non-flammable propellant with the sealant and the non-flammable propellant; wherein the composition has a vapor pressure less than about 180 psig at 130xc2x0 F.
Additional aspects of the invention and advantages provided by the embodiments of the invention are apparent with the following description.
Not applicable.